A high speed, high efficiency transportation system utilizes a low-pressure environment in order to reduce drag on a vehicle at high operating speeds, thus providing the dual benefit of allowing greater speed potential and lowering the energy costs associated with overcoming drag forces. In embodiments, these systems may use a near vacuum (e.g., low-pressure) environment within a tubular structure. The entire span of the tube, which is potentially hundreds of miles, is maintained at a low pressure, and thus, air is evacuated from the tubular structure in order for the system to operate.
Specific portions of the tube may need to be regularly re-pressurized, and discrete portions of the tube may need to be capable of depressurization for access thereto (e.g., for routine maintenance and/or emergency procedures). As the current state of the art does not encompass partially evacuated large diameter tubes for transportation, substantial thought has not be given to creating airlocks in such an environment. Thus, there exists a need in the art for improved gate valves and/or air locks for a high-speed transportation system.